The .cpvs files (this is the right extension writing) are made to hide some PSDL terrain blocks depending by the position of the camera for the purpose of have less lag in-game. So, with them the city blocks and PKGs above them aren't entirely and always rendered, yeah, but has also been demonstrated that the game doesn't crash and works pretty well when all the PSDL terrain blocks result visible (the .cpvs file is "switched off" by replacing it with an empty file) plus with increased drawing distance limit. Don't you remember the Dummiesboy's discover about this?
That aspect of the game working is not influent for the game crashes while the city loading. The game always loads the entire geometry and textures of the city, the cars and all the rest, and when it's too much for it, combined with the screen resolution and some other aspect probably, will result in the crash. The known game memory limits...
The PSDL terrain is subdivided in blocks because it works in this way, and each block is of a different kind, from those for the simple terrain to those used for roads and intersections connected with the traffic working.
So, if the cities would be extractable and joinable with software, MM2 would load them correctly?
Probably not, or at least, to get a chance of working, you'll have to play the game in 640x480 screen resolution, with software rendering, using a low polygons player car, set no traffic and set no pedestrians. All this, to compensate the too high number of polygons and other to load for only the city, which will saturate the memory using limits of the game.
This topic is now going away, and its finality was already clear since the beginning. The subject hasn't and practically can't be taken seriously, indeed.